Study: How a photo of a dirty toilet can predict one's politics

In this Friday, Oct. 29, 2010 file photo, voters in voting booths are blurred by the action of a zoom lens at the Oklahoma County Election Board during early voting in Oklahoma City.
(AP Photo/Sue Ogrocki, File)

What can pictures of maggot infestations, mutilated animals, dirty toilets, and rotting corpses tell you about a person's political affiliation? A lot, apparently. Researchers led by Virginia Tech scanned people's brains as the subjects looked at disgusting images, and they found that the strength of the brain responses could predict—with up to 98% accuracy—whether a person was liberal or conservative ...

even when those responses don't correspond to how the subject consciously reacted to the image. Researchers found that conservatives had more magnified responses to the repulsive photos.

As they write in Cell Biology, the brain's reaction to a single gross image was "remarkably ... sufficient to make accurate predictions about an individual subject’s political ideology." Why? As the lead researcher explains, previous research has found political affiliation to be "almost as heritable as height," and disgust reactions are also likely inherited.

As a press release puts it, "the responses could be a callback to the deep, adverse reactions primitive ancestors needed to avoid contamination and disease. To prevent unsavory consequences, they had to learn to separate the canteen from the latrine." As such, "some 'knee-jerk' reactions to political issues may be simply that—reactions," the lead researcher says.

As Reason notes, previous studies have uncovered similar findings: One found that conservatives get disgusted more easily, while another found that those who aren't very easily disgusted tend to be liberal.